Cable seals are in wide use and comprise a self-adjusting cable gripping unit which automatically adapts itself to gripping a stranded cable. In such use, a cable is typically formed with a swaged flag at one end to form an integral head member for the cable end. The other end of the cable is free. The cable free end is slipped or otherwise passed through an opening of a structure to be locked, for example, two hasps of a lock arrangement or other arrangement in doors, walls and the like for securing two elements together.
After the cable is slipped through the hasps or other lock arrangement, the cable gripping unit receives the free end of the cable and the cable is slid through the unit which has a bore therein including a cable gripping structure comprising segments within the bore which spread apart and slide over the cable as the unit is slid along the cable. When the unit reaches a desirable position adjacent to the hasp or other structure to which the cable is to be locked the unit is left in place at that location. Any attempt to remove the unit by sliding the unit in a reverse direction along the cable is precluded by the gripping structure within the unit bore. If the gripping structure is attempted to be displaced in the reverse direction by displacing the cable, the cable is gripped by the gripping structure as the cable is displaced and the gripping structure wedges against the cable and unit housing locking the cable thereto. The gripping unit housing and the flag at opposing ends of the cable lock the cable and the hasp together.
In U.S. Pat. No. 3,852,850 for example, a cable gripping unit is disclosed. This unit includes a helical spring, a cable receiving cup and a gripping member comprising a jaw retaining member and jaw segments. A shell formed of metal has a bore terminating in a cable accommodating opening and a cylindrical portion terminating in a reduced diameter opening providing an inwardly projecting annular shoulder. The gripping member and jaw segments are received in the bore. The gripping member is urged toward a reduced end of the opening of the gripping unit shell. The jaw retaining member is formed of an elastic material with the jaw segments held in slots in the retaining member. A spring urges the jaw segments in wedging engagement in the shell bore. This structure requires a number of different elements including separate jaw segments and a jaw retaining member. A problem with this structure as recognized by the present inventors is the need for the additional jaw retaining member. Additional structure adds cost.
U.S. Pat. No. 3,868,748 ('748) discloses a tendon gripping and release assembly somewhat similar to that disclosed in U.S. Pat. No. 3,852,850. In the '748 patent, a tapering casing housing includes spring compressed wedge segments arranged to form a bore therebetween for reception and retention of a steel tendon inserted in the casing. The wedged segments are urged towards the small end of the tapering casing by a spring. An elongated release member extends transversely through the small end of the tapered casing and engages one end of the wedge segments. The release member urges the wedged segments rearwardly against the tension of a spring to release the grip on the tendon and permit removal thereof from the assembly. This structure may have the same problem addressed above.
In those instances where it is not desirable to release the tendon, the use of a release mechanism as disclosed in this patent is not desirable. For example, where it is desired to permanently lock a hasp or other structure together, a release mechanism is not needed.
In U.S. Pat. No. 3,994,521, a portable cable lock is employed with a ball detent mechanism. The balls provide similar action as that of the wedge segments in the patents discussed above. In this arrangement, a locking shell is formed with a central passageway which is internally tapered with an opening that changes from conical to triangular and which carries spring loaded ball bearings and a retainer such that a cable can be inserted through the central opening in a first direction. This depresses the spring and allows the balls to relieve pressure on the cable in the first direction but which provide substantial locking pressure on the cable when the cable is placed under tension in the opposite direction. A still further arrangement is disclosed in U.S. Pat. No. 1,577,678 which discloses a fastening means employing a similar type of cable gripping structure. U.S. Pat. No. 899,776 discloses a trolley wire splicer employing a number of jaws. This arrangement is somewhat similar to that disclosed in the U.S. Pat. No. 3,852,850 patent discussed above.
The present inventors recognize a need for a low cost simplified locking device for securing a rod or cable thereto employing segments without the need for an additional separate element to hold the segments together.